Question 12.C-L.3: Determine which of the following can exhibit geometric isome...
Determine which of the following can exhibit geometric isomerism, and draw structural formulas for the cis and trans isomers of those that can:
a. CH _{2}= \underset{\overset{|}{CH_3} }{C} – CH _{2}- CH _{3} c. CH _{3}-\underset{\overset{|}{CH_3} }{C} = CH – CH _{3}
b. CH _{3}-\underset{\overset{|}{CH_3} }{C}H-CH = CH – CH _{3}
a. This structure does not exhibit geometric isomerism because there are two H’s attached to the carbon at position 1.
b. \underset{cis}{\begin{matrix}H &&&&\quad H\\\diagdown &&&&\diagup\\ &C&=&C\\\diagup &&&&\diagdown \\CH_3-CH &&&&CH_3\\\quad\quad|\\ \quad\quad\quad CH_3\end{matrix}} \underset{trans}{\begin{matrix}H &&&&\quad CH_3\\\diagdown &&&&\diagup\\ &C&=&C\\\diagup &&&&\diagdown \\CH_3-CH &&&&H\\\quad\quad|\\ \quad\quad\quad CH_3\end{matrix} }
c. This structure does not exhibit geometric isomerism because there are two methyl groups attached to the left double-bonded carbon.